Data Obfuscation


This feature transforms sensor data for privacy concerns, where raw data are obfuscated. It is an opt-in feature and is supported by the sensors below
  • GPS
  • Bluetooth BLE Proximity
Nearness is the only obfuscation method available for both sensors.

Nearness (Bluetooth)
When enabled for BLE, the data to be obfuscated is the raw RSSI reading. The raw RSSI values are mapped into categories for each device and its interactions. Below are the readings to categories mappings.

RawRSSI Range
Category
-127 to -120
A
-119 to -110
B
-109 to -100
C
-99 to -90
D
-89 to -80
E
-79 to -70
F
-69 to -60
G
-59 to -50
H
-49 to -40
I
-39 to -30
J
-29 to -20
K
-19 to -10
L
-9 to 0
M
1 to 10
N
11 to 20
O

Sample output
No
Raw Data
Obfuscated Data
1
[ { "rawRSSI": "0", "deviceName": "SELF_ODIN_xxx_xxx_abcdefghij_DISCOVERABLE", "smoothedRSSI": "0.0" }]
{
"abcdefghij": "M"
}
2
[ { "deviceName": "SELF_ODIN_xxx_xxx_abcdefghij_DISCOVERABLE", "rawRSSI": "0", "smoothedRSSI": "0.0" }, { "deviceName": "ODIN_xxx_xxx_zyxpqrstuv", "rawRSSI": "-97", "smoothedRSSI": "-97.0" }]
{
"abcdefghij": "M",
"zyxpqrstuv": D
}
3
[ { "rawRSSI": "0", "smoothedRSSI": "0.0", "deviceName": "SELF_ODIN_xxx_xxx_abcdefghij_DISCOVERABLE" }, { "rawRSSI": "-98", "smoothedRSSI": "-98.0", "deviceName": "ODIN_xxx_xxx_zyxpqrstuv" }, { "rawRSSI": "-81", "smoothedRSSI": "-81.0", "deviceName": "ODIN_xxx_xxx_qwertyuiop" }]
{
"abcdefghij": "M",
"zyxpqrstuv": "D",
"qwertyuiop": "E"
}


Nearness (GPS sensor)
When enabled, this feature obfuscates the longitudinal and latitudinal coordinates of the participant's device. Based on the GPS rules defined for the survey, we calculate the distance between the device and the rule locations and when this falls within the rule radius, the data is included in the obfuscated form with the rule identifier and distance.


Assuming a study has 2 GPS rules
    Multilocation rule with 3 location
Line No
Latitude
Longitude
Radius (in meters)
1
17.89
18,90
30
2
20.56
8,01
50
3
14.32
11.43
10
    On-arrival rule
Line No
Latitude
Longitude
Radius (in meters)
1
12.39
3.49
60


Sample output
No
Raw Data
Obfuscated Data
1
{ "latitude":"-1.0", "longitude":"-1.0"}
{
"1":{},
"2":{}
}
2
{ "latitude":"50.353262", "longitude":"10.1283316"
}
{
"1":{
"1": 21.4,
"3": 4.5
},
"2":{
"1":33.8
}
}
3
{ "latitude":"15.741895", "longitude":"10.989308"}
{
"1":{
"1": 18.9,
"2": 26.6,
"3": 9.5
},
"2":{}
}

Obfuscated rows
    The device was not within the radius of any of the defined rules
    The device was 21.4 and 4.5 meters from multilocation rules 1 and 3 respectively as well as 33.8 meters from the on-arrival rule
    The device was 18.9, 26.6 and 9.5 meters from multilocation rules 1, 2 and 3. but not within the radius of the on-arrival rule